Definition
A free ground-based service, available in the United States through the ADS-B network, that broadcasts traffic information to suitably equipped aircraft. TIS-B uses surveillance data from FAA radar and other sources to send the position, altitude, and velocity of nearby aircraft that are not transmitting ADS-B Out, allowing ADS-B In equipped aircraft to see those targets on a cockpit display.
Plain English
A service that lets your aircraft display see other airplanes around you, even ones that don't have the newer broadcast equipment, by sending their positions up from ground radar.
Context Anchor
A pilot encounters TIS-B when using cockpit traffic displays, ADS-B In equipment, or FAA material about traffic awareness services.
Derivation
"Broadcast" here means information sent out to all suitably equipped receivers in an area, rather than directed to one aircraft. This distinguishes TIS-B from the older TIS, which sent traffic to one aircraft at a time over a transponder data link.
Why Pilots Care
Improves situational awareness and supports visual acquisition of traffic that would otherwise remain unseen.
Intuition Check
Do not assume “traffic information service” means a complete traffic picture. TIS-B shows traffic known to the system and received by your equipment; it does not replace visual scanning or pilot responsibility to avoid other aircraft.
Example Sentence 1
After takeoff, the pilot watched a TIS-B target appear on the cockpit display, indicating another aircraft crossing two miles ahead.
Example Sentence 2
TIS-B showed a slow-moving target that turned out to be a helicopter operating below the approach path.